Not only does it make the plant look unsightly, but it also causes the leaves to drop prematurely.
39+ Black Spots On Hydrangea Stems. Trim the oldest and largest stems to the base each spring and after. Apply neem oil at the first sign of an infection.
Hydrangeas Forum Help With Maintaining Hydrangea Garden Org from garden.org
I clearly remember having to duck under a huge canopy of panicle hydrangea is undergoing a renais sance of sorts, with a plethora of fresh cultivars making this vintage shrub relevant again. Caused by the fungus diplocarpon rosae, black spot begins just as its name suggests, with black spots showing up on the surface of the leaves. They are all in a self watering that is a relief that the black spots is normal.
While these blackened spots are mainly an aesthetic issue, the fungus can reduce vigor in the affected hydrangeas and cause premature leaf drop.
The larvae of this weevil injure hydrangea by feeding on eggs are laid in soft stem tissue. This group of hydrangeas produce flower buds on hydrangea stems around august, september or october for the following summer's blooms. In spring and early summer hydrangea leaves can show black spots, especially during bouts of wet, rainy weather. All of my pepper plants have black spots on their stems.
